#include<stdio.h>

int n;
int main()
{
    scanf("%d", &n);
    double sum = 0;
    int cnt = 0;
    for (int i = 1; i <= n; i++)
    {
        int tmp;
        scanf("%d", &tmp);
        if (tmp % 2 == 1)
        {
            sum += tmp;
            cnt++;
        }
    }
    printf("%.1lf", sum / cnt);
    return 0;
}